1. Field of Invention
This invention relates to photographic equipment, specifically to a Flash Bracket with a Shutter-Synchronized Spotlight for the purpose of facilitating photography under poor lighting conditions.
2. Description of Prior Art
Throughout this text, the term flashlight refers to the portable, normally handheld spotlight used by persons at night. The term, flash or flash unit, refers to an electric lamp, most often used for producing a high-intensity light of very short duration for use in photography.
Flash brackets of various sizes and shapes are well known in the art. A flash bracket is typically a framework of some sort that connects a camera body with a flash unit. This allows the flash unit to be supported off camera, so that the flash may be aimed more precisely at a subject. This is especially important with close-up photography. Thus flash brackets serve as a third hand for holding the flash unit. This configuration is popular with nature photographers because of its portability. Most flash brackets on the market today, are designed without any provision for a spotlight. The manufacturers of flash brackets assume that the photographer will be working with enough ambient light to render the subject in the camera viewfinder in focus. This assumption falls short of reality for many photographers involved in the pursuit of nature photography. The vast majority of wildlife is active at night, or confined to the shadows, where a photographer is required to use a flash unit in order to photograph them. For a photographer to work under these low light circumstances, a spotlight is necessary to illuminate a subject so that a pleasing, focused composition can be achieved. To this end, many nature photographers need an assistant equipped with a flashlight to help illuminate a subject in preparation for making the photograph. Some photographers find various means of attaching small flashlights to their flash units, or to some point on their flash bracket so that a subject can be illuminated for viewing through the camera viewfinder. Some photographers try using a headlamp as a spotlight. These solutions still have significant problems:                a) When a headlamp is used for a spotlight, the headlamp is difficult to get pointed at the subject while the photographer is peering through the viewfinder. This is especially so because the flash unit tends to be in the way of where the spotlight needs to be pointing. Even worse, night flying insects are attracted to the light, which is mounted directly on the users forehead.        b) Only small, AA type flashlights are practical for attaching to a flash bracket for purposes of having a spotlight to be used to aid focusing. However, the light from this source is weak and limited in range. A standard D size 3-cell flashlight provides ample light, but is too much bulk to attach to a flash bracket, and severely reduces the portability of the setup.        c) In both cases, A and B, the light must be turned on in anticipation of making a photograph, and remain on until the photographic session is over. This is because most photo opportunities are extremely fleeting, and the time it takes to remove ones eye from the viewfinder to turn on the spotlight, and then to return ones eye back to the viewfinder to make the shot is not practical.        d) In many cases the photographer is trying to photograph subjects that shun bright light, thus having such a constant light trained on the subject will generally elicit a lack of cooperation from the subject and may adversely prolong the photographic session.        e) Most nature photographers must endure long periods of waiting for their subjects to cooperate before a photograph can be made. This often means that the spotlight will be on, hence using up precious battery power, hence weakening the strength of the light (already a problem for the small flashlight) before any photography is done.        f) As mentioned, an assistant can be used to provide the service of spotlighting the subject with a standard size flashlight, thereby freeing the photographer of this chore. There are several problems with this arrangement. Nature photography requires a huge amount of concentration and patience. Generally, the person doing the spotlight duty does not feel as committed to the situation as the photographer. The photographer feels hurried by having a second person involved, and the necessary concentration and patience are lost. It is much better for the photographer to be able to work independently.        g) In addition to the problems of using an assistant, the use of a standard flashlight provides ample light, which then becomes a liability. The light from a standard D size 3-cell flashlight with fresh batteries is bright enough to make an exposure contribution to the final image in the photograph. This results in an effect known as “ghosting”. This is because at the slow shutter speeds required to synchronize flash, a bright spotlight is too close to daylight exposure so you end up with a ghost image from the spotlight and another sharper image from the flash. So whereas a weak spotlight is aggravating to use, it will not make a contribution to the exposure of the image, thus avoiding the ghost image. The flash unit with its bright, short duration, will be the only significant light source, and will result in a sharp image. In contrast, a bright spotlight is comfortable to use, but it contributes to some of the exposure of the image and will cause the ghosting effect. As a result of all this, photographers end up favoring the small, weaker penlights to help them focus, while enduring the barely adequate light, and limited range they provide. My invention provides a way to use a comfortably bright focusing light without the ghosting effect.Additional Explanation of the Problem Known as “Ghosting”        
A photographic image is created when light passes through a lens and casts the resulting image (focused light) onto film. Film acts like a light collector. The length of time it takes to expose the film to make a successful photograph will depend on how strong the light is. An analogy for the photographic process is one where a cup is being filled with water. The goal is to fill the cup with only the amount of water it takes to fill it. No more or less will do. If the water comes out of a faucet as a trickle, the period of time to fill the cup will be longer than if the faucet is on all the way. The same is true of the way film collects light. If the available light is dim, the period of time to make the exposure will be longer than if the light comes as one big, bright, pulse. Either way, enough water is collected to result in a filled cup, and enough light is collected to result in a photograph.
If a photographer is working in a poorly lit room, the situation will require a slower shutter speed to get enough light to collect onto the film to make an image. For the sake of this explanation, lets say the camera shutter needs to be open for two full minutes in the poorly lit room of our example, to allow the film to be properly exposed. To make our photograph, we must open the camera shutter, and wait out the 120 seconds it takes to gather enough light from the subject being photographed to get an image on film. If the subject remains still throughout the exposure, the result will be a sharp picture of our subject. Now lets say we want to make a second photograph, using a different technique. For the sake of this explanation, lets say that we have available a flash unit that is capable of providing in one short pulse, the same amount of light that would otherwise take two minutes to collect from the poorly lit room to make the image. This means, if we want to make a photograph in our poorly lit room, we can just open the camera shutter, fire the flash unit, and then immediately close the camera shutter. In this way, using a flash, we will have supplied the necessary amount of light (plus a negligible amount of light from the room as we manually open and then close the shutter) to make the photograph. Assuming that we were able to open the shutter, fire the flash unit and close the shutter in just one second, for all practical purposes, the flash unit will have provided the only significant source of light. (Only {fraction (1/120)} of the room light got in). Indeed, flash units provide a bright light source at an amazingly short duration, so the image exposed in this way is effectively rendered onto the film in a millisecond! Even if the subject is moving, no significant image movement will be recorded because of the short duration of the flash and essentially no exposure will come from the light in the room since we still need 119 more seconds to make an image in that way. Such techniques have been used to photograph a bullet fired from a rifle. The resulting photograph shows a bullet that appears suspended in the air! Now lets make another photograph in our poorly lit room, but this time we don't close the shutter after the flash is fired. Instead, we finish out the 120 second exposure and then close the shutter. In this case we will end up with a double image. We will end up with the sharper image that was produced by the flash and a blurred image (if the subject is moving) from the remainder of the 120 second exposure. The second blurry image often looks like a ghost, hence the term “ghosting” is applied to this result. If the subject is a stationary one, the result will be an overexposure of the subject. Ghosting and overexposure are some of the problems my invention solves. If a flashlight with fresh batteries is being used to provide light to aid in focusing on a subject, the light can be bright enough to cause the ghosting or overexposure effect over the flash unit exposure, exactly as explained earlier. Many older cameras require a modest shutter speed, of {fraction (1/60)} second, in order to get the flash to fire while the shutter is still open (this is called the flash sync shutter speed of the camera). So even though the flash has done its job in milliseconds, the flash sync shutter speed of the camera is slow and enough light, from say a bright flashlight, may be allowed to collect on the film to cause unwanted additional exposure, long (relatively speaking) after the flash exposure has occurred.
Description of Prior Art References
Inventors have sought to create an apparatus which facilitates the focusing of a camera under conditions of darkness or poor light. U.S. Pat. No. 4,067,030 to Kuramoto (1978) shows a spotlight focusing aid that may be built directly into a camera, or built into a flash unit. Kuramoto attempts to solve the problem of ghosting by several means. Regarding flash units, Kuramoto has designed one embodiment wherein the spotlight will turn off automatically in response to the discharge of the flash's capacitor. However, I learned from my experiences testing my own invention that if a spotlight is being used that provides as bright a light as the spotlight of my invention, it would be impossible for the filament of the light bulb to cool down fast enough to be no longer emitting light during the shutter release sequence. Indeed, it would be as if the light was never shut off at all. Most cameras during the period of Kuramoto's patent had a top shutter sync speed of {fraction (1/60)} of a second. Kuramoto admits in his specification that the spotlight will still be on at the start of the shutter release sequence of his invention. This means that the bulb filament has to go cold in much less than {fraction (1/60)} of a second for Kuramoto to have succeeded in his design. Kuramoto's design works because he is using a relatively dim spotlight. This would be necessary because a stronger light would not be able to shut off quickly as explained. A stronger light would also compete with the capacitor of the flash unit for power thus slowing the recycle time for the flash unit. This would be an unacceptable compromise for most photographers. To conserve power, and solve the problem of filament cool down, Kuramoto has developed a novel approach to the manner in which his spotlight works. Rather than illuminating the whole of a photographic subject, Kuramoto's invention conserves power by reducing the spotlight output to a small circle of light, which can then be placed upon a very limited portion of the subject to be photographed. Then, using the split-image focusing aid that was common to many cameras of that time, the out-of-focus circle of light would be seen as two distinct circles of light. To achieve focus, these are brought into registration with each other by rotating the focusing ring of the picture-taking lens. There are many problems with this arrangement. The subject of the photograph would be essentially impossible to evaluate for compositional appeal since the method just described only provides a way to focus by using an indirect means that fails to illuminate the entire scene. Furthermore, since 1986, most camera manufacturers have abandoned the split image focusing aids because in reality they were annoying to use. Today, the preferred focusing screens have grid lines or other etchings that the photographer can easily look past to see a subject for the purpose of focusing. In the Nikon system, these screens are called “E” screens. Canon calls them “D” screens. The focusing aid of the split focus type screens were impossible to look past for purposes of focusing the subject directly. In any case, there are many subjects that would be difficult to hit with the small circle of light of Kuramoto's invention. For instance, a popular nature image such as a dew-covered spider web would be a difficult subject using the aforementioned technique. This is because the subject is translucent. However, Kuramoto's invention would be unsuitable for all close-up photography. One of the laws of optics is that as magnification increases, depth of field dramatically decreases. Therefore, only being able to see and focus on a small portion of a close-up subject will guarantee a bad result. The spider web example is a photographic subject that falls into a narrow plane. To have the entire subject in focus, it is necessary to carefully line up the camera's film plane so that it is parallel to that of the subject plane. This can not be done if only a part of the subject is being illuminated. Depth of field is so limited that there is not much leeway for error. To determine focus and composition, it is necessary for the entire subject, especially in close-up photography, to be illuminated to make the proper judgments. Kuramoto discusses other embodiments wherein the spotlight is built into a camera body. But these suffer the same drawbacks as already mentioned and may have additional drawbacks. For instance, Kuramoto explains that the spotlight may be automatically angularly adjusted by the camera focusing mechanism in accordance with the object distance to compensate for parallax. However, this approach would commit the picture taking lens to a link mechanism of some sort that would likely obviate interchangeable lenses for this type of camera. Interchangeable lenses are the main benefit of 35 mm cameras, which are the preferred choice of nature photographers. U.S. Pat. No. 5,142,299 to Braun; Bradley S. (1992) shows a focusing system that comprises two spotlights that intersect at a predetermined point of focus. Thus the placement of a photographic subject at this intersection point allows the photographer to work without even looking through the camera viewfinder. This technique is adequate for the demanding conditions of underwater photography that is the primary use of the invention of Braun and Bradley. However, outside the aquatic environment, the invention of Braun and Bradley is susceptible to many of the problems, A through G, already listed earlier in this discussion of prior art. The October 2001 issue of National Geographic, pp. 130, shows a photograph of a photographer at work using a penlight spotlight as a focusing aid. This photograph helps to demonstrate that photographers are currently still enduring the problems I have described and that my invention solves.
Objects and Advantages
The objects and advantages of the present invention are:                a) To provide a spotlight that is easy to point towards the subject to be photographed;        b) To provide a spotlight that is bright as a 3 D-cell standard flashlight, yet is lightweight and will not reduce the portability of the bracket setup;        c) To provide a spotlight that is powered by connecting the spotlight to a remote battery pack, thus eliminating the bulk load at the spotlight position, and isolating any corrosion damage from battery leakage off of the spotlight assembly;        d) To have a spotlight system with greater range so that the bracket setup is not limited to close-up photography;        e) To provide a spotlight that will produce light immediately on demand rather than continuously;        f) To provide a spotlight that will not unduly disturb the subject to be photographed;        g) To provide a spotlight that conserves battery power;        h) To provide a spotlight system that will work with any camera, old or new, that uses a remote push-button means such as a standard cable release or electronic cable release;        i) To provide a spotlight that allows the photographer to work without the collaboration of another individual;        j) To provide a spotlight that will not cause a “ghosting” effect to be produced in the resulting image; and        k) To provide a spotlight that employs a very simple and reliable switching mechanism that is easy to manufacture.        
Further objects and advantages are to provide a spotlighting system that is simple to use and inexpensive to manufacture. The present invention provides a spotlighting system that is rugged and durable for use in the field. Still further objects and advantages will become apparent from a consideration of the ensuing description and drawings.
A First Preferred Embodiment—FIGS. 1 to 23 and FIGS. 31 to 36